Presents Scientists as they chart a course for a healthy planet and reveal our world in ways that were never possible before the space age. On the way to the moon we discover another world: our own. The photo of earth from space perhaps the most important of the 20th century--began the transformation of humankind's understanding of earth as a living system. Now the technology developed to explore other planets is being used to monitor this living system. How will satellites merged with powerful computers help peer into the future to help predict global temperature and changes in the cydes of life.